Management of Preexisting Diabetes in Pregnancy

Abstract

Importance: The presence of preexisting type 1 or type 2 diabetes in pregnancy increases the risk of adverse maternal and neonatal outcomes, such as preeclampsia, caesarian section, pre-term delivery, macrosomia and congenital defects. Approximately 0.9% of the 4,000,000 births in the United States are complicated by preexisting diabetes. Observations: Women with diabetes have increased risk for adverse maternal and neonatal outcomes and similar risks are present for either type 1 or type 2 diabetes. Both forms of diabetes require similar intensity of diabetes care. Preconception planning is very important to avoid unintended pregnancies, and to minimize risk of congenital defects. Hemoglobin A1c goal at conception is <6.5% and during pregnancy is <6.0%. It is also critical to screen for and optimize comorbid illnesses such as retinopathy and nephropathy. Medications known to be unsafe in pregnancy, such as angiotensin-converting enzyme inhibitors and statins, should be discontinued. Obese women should be screened for obstructive sleep apnea, which is often undiagnosed and can result in poor outcomes. Blood pressure goals must be considered carefully, as lower treatment thresholds may be required for women with nephropathy. During pregnancy, continuous glucose monitor use can improve glycemic control and neonatal outcomes for women with type 1 diabetes. Insulin is first-line therapy for all women with preexisting diabetes; injections and insulin pump therapy are both effective approaches. Rates of severe hypoglycemia are increased during pregnancy; therefore glucagon should be available and close contacts trained in its use. Low-dose aspirin is recommended soon after 12 weeks of gestation to minimize the risk of preeclampsia. The importance of discussing long-acting reversible contraception before and after pregnancy cannot be overstated, to allow for appropriate preconception planning. Conclusions and Relevance: Preexisting diabetes in pregnancy is complex and is associated with significant maternal and neonatal risk, but optimization of glycemic control, medication regimens and careful attention to comorbid conditions can help mitigate these risks, and ensure quality diabetes care before, during and after pregnancy.

Preconception diabetes mellitus and adverse pregnancy outcomes in over 6.4 million women: A population-based cohort study in China

“…With the aging of the population, urbanization, and related dramatic changes toward sedentary lifestyle during the past few decades, the prevalence of diabetes mellitus (DM) has been growing rapidly worldwide [1][2][3]. The number of people aged 18 years or older with DM globally is projected to rise from 451 million in 2017 to 693 million in 2045 [4].…”

Glycemic control and fetal growth of women with diabetes mellitus and subsequent hypertensive disorders of pregnancy

“…Among women with T2DM, the frequency of T2DM + HDP was similar between women with and without diabetic nephropathy (33.3% versus 11.3%); furthermore, the frequencies of women with T2DM + HDP or CH were similar (50.0% versus 28.9%). A recent review determined that it is also critical to screen for and manage retinopathy and nephropathy, and blood pressure goals must be considered carefully because lower treatment thresholds may be required for women with nephropathy [2].…”

“…The target HbA1c levels are <6.5% at conception and <6.0% during pregnancy. During pregnancy, continuous glucose monitoring can improve glycemic control and neonatal outcomes in women with T1DM [2]. Another review of pregnant women with T1DM indicated that the goals of preconception care are tight glycemic control with an HbA1c level of <7.0% and as close to 6.0% as possible, and the target HbA1c level during pregnancy is <6.0%.…”

“…However, in women at risk of preeclampsia, prophylaxis with low-dose aspirin (particularly when initiated less than 16 GW) may reduce the risk of FGR [48]. In a recent review article, low-dose aspirin was recommended soon after 12 GW to minimize the risk of preeclampsia in women with T1DM [2]. Some obstetricians indicated that pregnancies complicated by T1DM and T2DM increase the risk of these complications, which are largely attributed to placental dysfunction.…”

“…DM was found to be a risk factor for preeclampsia in a systematic review. [2] The odds ratio [95% confidence interval (CI)] of preeclampsia in pregnant women with preexisting DM versus their counterparts without DM was 3.48 (3.01-4.02) in the US [3]. Furthermore, the incidence of T2DM in Japanese populations is higher than that in the US or western European populations.…”